github.com/orangenpresse/up@v0.6.0/http/static/static.go (about)

     1  // Package static provides static file serving with HTTP cache support.
     2  package static
     3  
     4  import (
     5  	"net/http"
     6  	"os"
     7  	"path/filepath"
     8  	"strings"
     9  
    10  	"github.com/apex/up"
    11  )
    12  
    13  // New static handler.
    14  func New(c *up.Config) http.Handler {
    15  	return http.FileServer(http.Dir(c.Static.Dir))
    16  }
    17  
    18  // NewDynamic static handler for dynamic apps.
    19  func NewDynamic(c *up.Config, next http.Handler) http.Handler {
    20  	prefix := normalizePrefix(c.Static.Prefix)
    21  	dir := c.Static.Dir
    22  
    23  	if dir == "" {
    24  		return next
    25  	}
    26  
    27  	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    28  		var skip bool
    29  		path := r.URL.Path
    30  
    31  		// prefix
    32  		if prefix != "" {
    33  			if strings.HasPrefix(path, prefix) {
    34  				path = strings.Replace(path, prefix, "/", 1)
    35  			} else {
    36  				skip = true
    37  			}
    38  		}
    39  
    40  		// convert
    41  		path = filepath.FromSlash(path)
    42  
    43  		// file exists, serve it
    44  		if !skip {
    45  			file := filepath.Join(dir, path)
    46  			info, err := os.Stat(file)
    47  			if !os.IsNotExist(err) && !info.IsDir() {
    48  				http.ServeFile(w, r, file)
    49  				return
    50  			}
    51  		}
    52  
    53  		// delegate
    54  		next.ServeHTTP(w, r)
    55  	})
    56  }
    57  
    58  // normalizePrefix returns a prefix path normalized with leading and trailing "/".
    59  func normalizePrefix(s string) string {
    60  	if !strings.HasPrefix(s, "/") {
    61  		s = "/" + s
    62  	}
    63  
    64  	if !strings.HasSuffix(s, "/") {
    65  		s = s + "/"
    66  	}
    67  
    68  	return s
    69  }